This document discusses rectal products and suppositories. It begins by defining rectal products as pharmaceutical preparations administered via the rectum for local or systemic effects. It then discusses the advantages and disadvantages of the rectal route of drug administration. Specific rectal products discussed include suppositories and enemas. The document provides details on the anatomy and physiology of the rectum and factors influencing drug absorption from the rectum. It describes the ideal properties of suppository bases and discusses commonly used bases such as cocoa butter and synthetic triglycerides.

1. Rectal Products
By
Gasper b
School of Pharmacy
Ruaha University College (RUCO)
1

2. Rectal Products
 Pharmaceutical preparations administered via
the rectum for local or systemic effect
 Rectal products may be:
 Solid unit dosage form
 Liquid unit dosage form or
 Semi-solid dosage form
 Rectal products of interest:
 Suppositories and related products
 Enemas
2

3. Rectal Route for Drug
Administration: Advantages
 When the patient is unable to use the oral
route
 Inflection or disease of GIT, nausea,
vomiting, unconsciousness, post-operation
and young, old and mentally disturbed
patients,
 For achievement of rapid systemic effects by
giving a drug is suitable solution as an
alternative to parenteral administration
3

4. Rectal Route for Drug
Administration: Advantages
 For drugs less suited for oral route;
 Cause GI side effects, insufficiently stable at
pH of GIT, susceptible to enzymatic
degradation, has first- pass effect, with
unacceptable/unpleasant taste (important
factor for children)
 Drug absorption may be easily discontinued in
an events of accidental overdose.
 Rate of drug absorption is not influenced by
ingestion of food of the rate of gastric empting
4

5. Disadvantages of rectal route
 Slow and incomplete absorption
 E.g. interruption of absorption by
defecation, especially with irritant drugs
 Surface area of rectum is far small for
absorption compared to that of small
intestine
 Fluid content of rectum is much smaller than
that of small intestine, may affect
dissolution of some drugs
 Microbial degradation may occur in rectum5

6. Drawbacks/Disadvantages of
rectal route
 Inter and intra-subject variation
 Development of proctitis
 Problems with large scale production of
suppositories and of achievement of a suitable
shelf life
 Demanding stringent/strict storage conditions
 Patient acceptability may be a problem, at
least in some countries
6

7. Therapy with the rectal route
 Local effect:
 In case of pain, itching and haemorroids
 Locally active drugs include astringents,
antiseptics, local anaesthetics,
vasoconstrictors, anti-inflammatory drugs,
soothing and protective agents and some
laxatives
 Systemic effect:
 Anti-asthmatics, anti-rheumatics and
analgesics
7

8. Anatomy and Physiology of Rectum
 The rectum is about
15 to 20 cm long.
 It hooks up with the
sigmoid colon to the
north and with the
anal canal to the
south.
 It is a hollow organ
with a relatively flat
wall surface, without
villi and with only
three major folds, the
rectal valves
8

9. Anatomy and Physiology of Rectum
 The terminal 2 to 3 cm
of the rectum is called
the anal canal.
 The opening of the anal
canal to the exterior is
called the anus.
 The anus is controlled
by an internal sphincter
of smooth muscle and
an external sphincter of
skeletal muscle.
9

10. Anatomy and Physiology of Rectum
 Under normal conditions, the rectum
emptying and filling provokes a defecation
reflex which under voluntary control.
 The transverse folds in rectum keep stool in
place until the person is ready to go to the
bathroom.
 Then, stool enters the lower rectum, moves
into the anal canal, and then passes through
the anus on its way out.
 Rectum contains about 2 to 3 ml of mucous,
which has a pH of 7.4 and little buffering
capacity
10

11. Anatomy and Physiology of Rectum
 The rectal tissues
are drained by the
inferior, middle and
superior
haemorrhoidal
veins, but only the
superior vein
connects with the
hepatic-portal
system
11

12. Absorption of drugs from the rectum
 Medicaments absorbed in the lower part of
the rectum are delivered directly into the
systemic circulation, thus avoiding any first-
pass metabolism.
 However, it has been found that
suppositories can settle high enough in the
rectum to allow at least some drug
absorption into the superior vein.
 Thus keeping the drug in the lower part of
the rectum would be advisable
12

13. Absorption of drugs from the
rectum
 Insertion of a suppository into the rectum
results in a chain of effects leading to the
bioavailability of the drug
 Depending on the character of the base, a
suppository will either dissolve in the rectal
fluid or melt on the mucous layer
 Since the volume of rectal fluid is so small,
complete dissolution of the base require extra
water
13

14. Absorption of drugs from the rectum
 Due to osmotic effects of the dissolved
base, water is attracted with a painful
sensation for the patient.
 Independent on the base type, dissolved
drugs in the suppository will diffuse out
towards the rectal membrane.
 The process of absorption will be passive
diffusion.
14

15. Physiological factors in rectal
absorption
1. Quantity of fluids available
 Very small volume under normal conditions
(3ml spread in a layer of approximately
100µm thick over the organ).
 Under non-physiological conditions (osmotic
attraction of water by water soluble base or
diarrhea), the volume is enlarged.
 Thus, absorption of slightly soluble drugs
(e.g. phenytoin) will be dissolution rate
limited
15

16. Physiological factors in rectal
absorption
2. Properties of rectal fluids
 Composition, viscosity, pH and surface
tension of rectal fluids have great effects
on drug bioavailability
3. Contents of the rectum
 Faecal content
16

17. Physiological factors in rectal
absorption
4. Motility of the rectum
 The rectal wall may exert a pressure on a
suppository present in the lumen by two
distinct mechanisms.
 First, the abdominal organs may simply
press on to the rectum when the body in
upright position
 This may stimulate spreading and
promote absorption.
17

18. Physiological factors in rectal
absorption
 4. Motility of the rectum (cont…)
 Second, the motility of the rectal muscle
associated with the presence of food in the
colon (waves of contractions running over
the wall of the colon)
18

19. Suppositories
 Suppositories are medicated solid-unit
dosage forms of various sizes (for adult and
pediatric) and shapes suitable for rectal
administration for local or systemic effect
 The medicament is incorporated into a base
such as cocoa butter which melts at body
temperature, or into one such as
glycerinated gelatin or PEG which slowly
dissolves in the mucous secretions
19

20. Suppositories
 Suppositories are suited particularly
for producing local action, but may
also be used to produce a systemic
effect or to exert a mechanical effect
to facilitate emptying the lower bowel
20

21. Formulation
 The AIs are dissolved or dispersed in a suitable
basis that should either melt at body
temperature, or dissolve or disperses in the
mucus secretions of the rectum
 Suppositories may also contain suitable
excipients such as:
 Absorbents, Absorption enhancers, Diluents
 Lubricants, Preservatives and Surfactants
 Shape, volume & consistency should facilitate
rectal administration
21

22. Suppos Shapes
22

23. Suppository Bases
 Like ointment bases, suppository base
composition is important in rate and extent
of release of medications.
 Suppository bases may be classified
according to their composition and physical
properties:
 Oleaginous (fatty) bases
 Water soluble or miscible bases
23

24. Specifications of Suppository
Bases
1. Origin and chemical composition
 The source of origin (i.e. entirely
natural or synthetic or modified
natural)
 Physical and chemical incompatibilities
with additives (i.e. preservatives,
antioxidants and emulsifiers)
24

25. Specifications of Suppository
Bases
2. Melting range
 Since fats do not have sharp melting point,
their melting characteristics are expressed
as a range indicating the temperature at
which the fat start to melt and the
temperature at which it is completely
melted.
25

26. Specifications of suppository
bases
3. Solidification point
 This value indicates the time required for
base to solidify when chilled in the mold
 If the interval between melting range and
solidification point is 10ºC or more, the
time required for solidification may have
to be shortened for a more efficient
manufacturing procedure by augmenting
refrigeration
26

27. Specifications of Suppository
Bases
4- Saponification value
 The number of milligrams of potassium
hydroxide required to neutralize the free
acids and to saponify the esters
contained in 1 gm of fat is an indication
of the type of glyceride (mono- or tri-)
as well as the amount of glyceride
present.
27

28. Specifications of Suppository
Bases
5- Iodine value
 This value express the number of
grams of iodine that react with 100 gm
of fat or other unsaturated material.
 The possibility of decomposition by
moisture, acids, and oxygen (leads to
rancidity in fats) increases with high
iodine values.
28

29. Specifications of Suppository
Bases
6- Water number
 Water number is the amount of water
in grams, which can be incorporated in
100 gm of fat
 The water number can be increased by
addition of surface active agents.
29

30. Specifications of Suppository
Bases
7- Acid value
 The number of milligrams of potassium hydroxide
required to neutralize the free acid in 1 gm of
substance is expressed by this value.
 Low acid values or complete absence of acid are
important for good suppository bases.
 Free acids complicate formulation work, because
they react with other ingredients and can also
cause irritation when in contact with mucous
membranes.
30

31. Suppository bases
The ideal suppository base should be;
 Nontoxic and nonirritating to sensitive and
inflamed tissues
 Inert and compatible with a broad variety of
medicaments.
 Easily manufactured by compression or
molding.
 Dissolve or disintegrate in the presence of
mucous secretions or melt at body temperature
to allow for uniform release of the medication.
 No meta stable forms
31

32. Follow; The ideal suppository base
 Remain molten for a sufficient period of time
to allow pouring into moulds.
 Solidify sufficiently rapidly to minimize
sedimentation of dispersed solids.
 Contract on cooling to allow easy withdrawal
of the suppository from the mould.
 Has wetting and emulsifying properties.
 High water number
 Stable on storage, does not change color,
odor and drug release pattern
32

33. Follow; The ideal suppository base
If the base is fatty, it has the following
additional requirements:
 Acid value is below 0.2.
 Saponification value ranges from 200 to
245.
 Iodine value is less than 7.
 The interval between melting point and
solidification point is small.
33

34. 1. Oleaginous (Fatty) Bases
Include:
 Theobroma Oil
 Synthetic
triglyceride
mixtures.
34

35. A- Theobroma Oil or Cocoa butter
 Theobroma Oil or cocoa butter is used as a
suppository base because, it fulfills most of
the requirements of an ideal base.
 Cocoa butter is primarily a tri-glyceride, it is
yellowish- white, solid, brittle fat, which
smells and tastes like chocolate.
 At ordinary room temperatures of 15° to
25°C it is a hard, amorphous solid, but at 30°
to 35°C i.e., at body temperature, it melts to
a bland (tasteless), nonirritating oil.
35

36. A- Theobroma Oil or cocoa butter
 Thus in warm climates, theobroma oil
suppositories should be refrigerated.
 Cocoa butter has iodine value between 34
and 38.
 Its acid value not higher than 4.
36

37. Disadvantages of theobroma oil
 Shrinks only slightly on solidification
 Requires a mould lubricant
 Exists in four polymorphic forms with
different melting points (18.9, 23.0, 28.0, and
34.5ºC).
 Theobroma should only be heated for a
short time and at temperatures below 36 ºC
in order to minimize the formation of the
unstable low melting point forms.
37

38. Disadvantages of theobroma oil
(cont…)
 The change (reduction) in melting point is
caused by addition of certain drugs such as
volatile oils, phenol or chloral hydrate to
cocoa butter suppositories.
 The solution is to raise the melting point back
to the desired range by addition of 3% to 5%
of beeswax or spermaceti.
38

39. Disadvantages of theobroma oil
(cont…)
 Theobroma oil has a low absorptive
capacity for water, but this can be increased
by adding surfactants such as cholesterol
2%, emulsifying wax up to 10%, polysorbates
5 to 10%, or wool fat 5 to 10%.
 However, the addition of surfactants may
lead to a drug- base interaction or affect the
release of drug from suppository
39

40. Disadvantages of theobroma oil
(cont…)
 Theobroma oil is prone to oxidation (due to
high iodine value)
 This can be partly overcome by storage in
a cool, dark place.
 Theobroma oil may vary in consistency, odor,
and color depending on its source like other
natural products.
 The low melting point of theobroma oil may
cause storage problems in hot climates
40

41. B. Synthetic Tri-glycerides (hard fat)
 They include synthetic tri-glycerides which
consist of esterified, hydrogenated or
fractionated vegetable oils.
 Their advantages over cocoa butter are:
1. Do not exhibit polymorphism
2. Contain mainly saturated acids (Iodine
number <3), while cocoa butter contains
considerable amount of the unsaturated
fatty acids (Iodine number 34-38).
41

42. B. Synthetic Tri-glycerides (hard fat)
3- The melting range of the synthetic bases is
usually about 3ºC higher than that of cocoa
butter
4- The acid content is lower (mostly <0.5)
5- Hard fat is a mixture of mono, di and tri-
glycerides of saturated fatty acids (C10 to C18).
The hydroxyl value of a base is determined
by proportions of mono and di-glycerides in
it. A higher hydroxyl value means the base
can absorb water more readily and less
suitable to easily hydrolyzed drugs.
42

43. B. Synthetic Tri-glycerides (hard fat)
6- Solidification temperatures of hard fats are
unaffected by over heating.
7- There is only a small temperature difference
between melting and solidification, thus the
sedimentation of suspended drugs is
minimized.
8- Mold lubrication is unnecessary since these
bases show marked contraction on cooling
9- Water absorbing capacity of hard fats can be
improved by inclusion of glyceryl
monostearate.
43

44. B- Synthetic Tri-glycerides (hard fat)
 They are, however, more expensive.
 A tendency to fracture upon pouring into
chilled moulds can be overcome by including
very small quantities of polysorbate 80.
 On prolonged storage, synthetic suppository
bases tend to crystallize, which causes
hardening and increases the melting time. This
can be reduced by storage in a cold place.
44

45. 2. Water Soluble/Water
Miscible Bases
 Water
Soluble/Water
Miscible Bases are
those containing:
A. Glycerinated gelatin
B. Polyethylene glycol
(PEG) polymers
47

46. A- Glycerinated Gelatin
 Glycerinated Gelatin is a useful suppository
base, particularly for vaginal suppositories
(Pessaries), where the prolonged localized
action is usually desired.
 Glycerinated gelatin suppositories are
translucent, resilient (flexible), gelatinous
solids that tend to dissolve or disperse
slowly in mucous secretions to provide
prolonged release of active ingredients.
48

47. A- Glycerinated Gelatin
 Suitable for use with a wide range of
medicaments including alkaloids, boric acid,
and zinc oxide
 Note:
 Suppositories made with glycerinated
gelatin must be kept in well-closed
containers in a cool place because they will
absorb and dissolve in atmospheric
moisture.
49

48. A- Glycerinated Gelatin
 Suppositories may have a dehydrating effect
and be irritating to the tissues upon insertion.
 The water present in the formula of
suppositories minimizes this action and the
suppositories may be moistened with water
prior to insertion to reduce the tendency of
the base to draw water from mucous.
50

49. A- Glycerinated Gelatin
 Also those suppositories intended for
extended shelf-life should have a preservative
added, such as methylparaben or
propylparaben, or a suitable combination of
the two.
 To facilitate administration, glycerinated
gelatin suppositories should be dipped in
water just before use
51

50. Preparation of glycerinated
gelatin rectal suppositories
 Mix or dissolve the medicaments in water to
make a total of 10 g.
 Add 70 g of glycerin and mix.
 Add 20 g of granular gelatin, mix carefully to
avoid incorporation of air.
 Heat on a steam bath until the gelatin is
dissolved.
 Pour the melted mixture into molds and allow to
solidify.
52

51. Example: Gycerol suppositories
 Glycerol suppositories are prepared according
to BP (Gycerol suppositories BP)
 Gelatin 14g
 Glycerol 70g
 Purified water qs
 Final product should weigh 100g
 The base is hygroscopic in nature
 Requres protection from heat and
moisture
53

52. Example: Gycerol suppositories
 What are the disadvantages of glycerol
suppositories BP?
 Dehydration of rectal mucosa i.e.
hygroscopic
 May support microbial growth hence
may requires addition of preservatives
54

53. Preparation of glycerinated
gelatin urethral suppositories
 The gelatin constitutes about 60% of the
weight of the formula, the glycerin about
20%, and the medicated aqueous portion
about 20%.
55

54. B- Polyethylene Glycol
Polymers
 Polyethylene Glycol Polymers possess
many desirable properties.
 They are chemically stable, nonirritating,
miscible with water and mucous
secretions, and can be formulated, either
by molding or compression, in a wide
range of hardness and melting point.
56

55. B. Polyethylene Glycol Polymers
Like glycerinated gelatin, they do not melt at
body temperature, but dissolve to provide a
more prolonged release than theobroma oil.
Certain polyethylene glycol (PEG) polymers
may be used singly as suppository bases but,
more commonly, formulas call for compounds
of two or more molecular weights mixed in
various proportions as needed to yield a
finished product of satisfactory hardness and
dissolution time.
57

56. B. Polyethylene Glycol Polymers
PEGs with average Mwt of 200, 400 and 600
are clear, colorless liquids.
Those with Mwt greater than 1000 are wax-
like, white solids with hardness increasing
with an increase in the molecular weight.
 Since water miscible suppositories dissolve
in body fluids and need not be formulated to
melt at body temperature, they can be
formulated with much higher melting points.
58

57. B. Polyethylene Glycol Polymers
This property permits a slower release of
medicaments from the base, safe storage at
room temperature without need for
refrigeration, and ease and slow insertion.
To prevent irritation of the mucous
membranes after insertion of PEGs
suppositories, they should contain at least
20% of water or dipped in water just prior
to use.
59

58. 3. Miscellaneous Bases
 Chemical or physical Mixtures of oleaginous
and water soluble or water miscible materials.
 Emulsions, generally of w/o type (i.e. mixing of
cocoa butter with emulsifying agents).
 Polyoxyl 40 stearate is a mixture of the mono-
stearate and di-stearate esters of mixed poly-
oxyethylene diols and the free glycols.
 Soap may be used as a base (i.e. Glycerin
suppositories, USP, with soap as the base).
61

59. Rectal Capsules
 Rectal capsule or shell suppositories are soft
gelatin capsules shaped like suppositories
 The content should be solid at room
temperature, like conventional suppositories
 Shell suppositories are suitable for use in
tropical climates, provided that containers
are hermetically sealed
62

60. Methods of Preparation
 Suppositories can be extemporaneously
prepared by one of three methods
1. Hand Rolling (Cold Compression)
 The oldest and simplest method
 May be used when few suppositories are to
be prepared in a cocoa butter base
 Advantage: no necessity of heating the
cocoa butter.
63

61. 1. Hand Rolling (Cold Compression)
 A plastic-like mass is prepared by triturating
grated cocoa butter and AIs using a mortar
and pestle
 The AIs are usually finely powdered,
dissolved in a little water, or mixed with
small amount of wool fat
 The mass is formed into a ball in the palm of
the hands, then rolled into a uniform
cylinder with a large spatula or small flat
board on a pill tile
64

62. 1. Hand Rollin (Cold Compression)
 The cylinder is then cut into appropriate
number of pieces which are rolled on one end
to produce a conical shape.
 Effective hand rolling requires considerable
practice and skill.
 The suppository "pipe" or cylinder tends to
crack or hollow in the center, especially when
the mass is insufficiently kneaded and
softened
65

63. 2. Compression Molding
 Is a method of preparing suppositories from
a mixed mass of grated (shredded)
suppository base and medicaments forced
into a special compression mold using
suppository making machines.
 The suppository base and the other
ingredients are combined by thorough
mixing.
 The friction of the process causes the base to
soften into a paste-like consistency.
66

64. 2. Compression Molding (cont…)
 On a small scale,
 Mortar and pestle may be used
 Preheated mortar facilitate softening of the base
 On large scale,
 Mechanically operated kneading mixers and a
warmed mixing vessel may be applied.
 In the compression machine, the suppository mass
is placed into a cylinder which is then closed.
 Pressure is applied from one end to release the
mass from the other end into the suppository mold
or die.
67

65. 2. Compression Molding (cont…)
 When the die is filled with the mass, a
movable end plate at the back of the die is
removed and when additional pressure is
applied to the mass in the cylinder, the
formed suppositories are ejected.
 The end plate is returned, and the process
is repeated until all of the suppository mass
has been used.
68

66. 2. Compression Molding (cont…)
 The method requires that the capacity of the
molds first be determined by compressing a
small amount of the base into the dies and
weighing the finished suppositories.
 When active ingredients are added, it is
necessary to omit a portion of the
suppository base, based on the density factors
of the active ingredients.
69

67. 3. Fusion Molding (Pour Molding)
 Fusion Molding involves:
 Melting the suppository base (heating above MP)
 Dispersing or dissolving the drug in the melted
base.
 The mixture is removed from the heat and poured
into a suppository mold
 Allowing the melt to congeal / solidify
 Removing the formed suppositories from the
mold.
 The fusion method can be used with all types of
suppositories and must be used with most of them.
70

68. Suppository Molds
 Small scale molds are
capable of producing 6
or 12 suppositories in
a single operation.
 Industrial molds
produce hundreds of
suppositories from a
single molding.
71

69. Lubrication of the mold
 Depending on formulation, suppository molds
may require lubrication before the melt is
poured to facilitate cleaning and easy removal
of the molded suppository (w/out breakage).
 Lubrication is seldom necessary if suppository
base is contract sufficiently on cooling.
 Lubrication is usually necessary when
glycerinated gelatin suppositories are
prepared
 E.g. of lubricants: Soap spirit
72

70. Displacement Values (DVs)
 DV of a medicament is the number of parts by
weight of a medicament that will displace one part
of suppository base (normally theobroma oil)
 Remember;
 Suppositories are prepared by dissolving or
dispersing an active medicament in a molten base
and pouring the mixture into a suppository mould
 Suppository molds are normally available in 1g, 2g
and 4g sizes etc
73

71. Displacement Values (DVs)
 Density of medicament affects amount of
base required for suppository
 It is thus necessary to make an allowance
for each medicament in terms of the
particular basis
 This allowance is the DV (defined)
 DVs for different drugs are constant (see
Pharmaceutical Codex)
74

72. Displacement Values (DVs)
 To calculate amount of basis required to
prepare a given number of suppositories,
the following formula is used;
 Wt of basis required = Total wt of supp
to prepare – (Total wt of AIs ÷ DV)
 Weight of basis required = total weight of
suppositories to be prepared –(total weight
of AIs / DV)
75

73. DVs: Example
 Calculate the quantities required to make 10
theobroma oil suppositories (2g mould)
each containing 400mg of zinc oxide (DV =
4.7)
– 19.15g
 How would you prepare 12 glycero-gelatin
suppositories, containing 0.5%w/w
cinchoncain HCl? Use a 2g mould
– 28.66g
76

74. Testing of Suppositories
 Finished suppositories are routinely
inspected for:
 Appearance
 Content uniformity
 Melting range test
 Drug release test
 Fragility test
 Disintegration test
77

75. Factors Influencing Absorption
 Physiologic factors (previously discussed)
 Physicochemical factors of the drug and the
base:
1- Lipid-water solubility of the drug
2- Particle size of the drug
3- Degree of drug ionization
4- Nature of the base
82

76. 1- Lipid-water solubility
 The lipid-water partition coefficient of the
drug is important in selection of suppository
base and in predicting drug release from that
base.
 A lipophilic drug that is distributed in a fatty
suppository base in low concentration has
less of a tendency to escape to the
surrounding aqueous fluids than a hydrophilic
drug in its saturation concentrations.
83

77. 1- Lipid-water solubility
 Water-soluble bases dissolve in rectal fluids
and release both water-soluble and oil-
soluble drugs.
 The more drug in the base, the more dug
will be available for potential absorption
 A drug with a high partition coefficient is
likely to be absorbed more readily from a
water soluble bases.
84

78. 2- Degree of ionization
 Absorption through rectal mucosa
proceeds in accordance with pH-partition
theory.
 At the slightly alkaline pH of rectal mucosa,
weakly basic drugs will exist in their lipid–
soluble unionized form and readily
absorbed.
85

79. 3- Particle size
 For drugs present in the suppository in the
un-dissolved form, the size will influence
the amount released and dissolved for
absorption
 The smaller the size, the more readily the
dissolution of the particle and the greater
the chance for rapid absorption.
86

80. 4- Nature of the base
 If the base interacts with the drug
inhibiting its release, drug absorption will
be impaired or even prevented
 If the base is irritating to the mucous
membranes of the rectum, it may initiate a
colonic response and prompt a bowel
movement, negating the prospect of
thorough drug release and absorption.
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81. Enemas
 Enemas are aqueous or oily solutions or
suspensions administered into the rectum and
colon via the anus for cleansing of the bowel
or delivering active drug
 Enema also refers to the procedure of
administering these preparations
 Types of enema:
 Evacuant Enemas
 Retention Enemas
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82. Enemas
1. Evacuant Enema:
 Used as a bowel stimulant to treat
constipation. E.g. Soft soap enema &
Mgso4 enema
 Volume of evacuant enemas may reach
up to 2 liters
 They should be warmed to body temp
before administration
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83. Enemas cont…
2. Retention enema:
 Volume does not exceed 100 ml
 No warming needed
 Retention enemas may exert:
 Local effect:
 Example
• Barium enema
– Used as a contrast medium in radiological
imaging of the bowel.

84. Enemas cont…
 Retention enemas: (cont…)
 Systemic effect:
E.g. administration of substances into
the bloodstream
This may be done in situations where
it is impossible to deliver a medication
by mouth, such as nutrient enema
which contains carbohydrates,
vitamins & minerals
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85. Enemas: Uses
 Enema are used for;
 Anti-inflammatory
 Laxative e.g. arachis oil enema
 Purgative
 Sedative effect
 X-ray examinations of the lower bowel
As contrast substance
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86. Packaging & Labeling
 Enemas
 Are dispensed in colored, fluted bottles
or in single-use plastic containers fitted
with a rectal nozzle for administration
 Suppositories
 Are supplied in partitioned boxes of
paper board, plastic, or metal
 They should be individually wrapped in
aluminium foil or waxed paper
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87. Packaging & Labeling
 Labeling
 All rectal preparations should carry the
auxiliary label
“For Rectal Use Only” Or
“Not to be Taken”
 For enemas, “Shake Before Use”, when
applicable
 For suppositories, “Store at a Cool Place”
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88. Assignment Questions
1. What are absorption enhancers? Supply one
example used in suppositories.
2. What are modified-release suppositories?
3. What are double layer suppositories?
4. Describe, briefly, the rectal conditions that affect
absorption of medicament from a suppository.
5. Give a brief account on “Bioavailability and
Suppositories”
6. Suppositories have an acceptability problem.
Comment.
7. Describe “anti-inflammatory enemas”.
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